Ovarian cancer is the most lethal malignant disease of the female genital tract. This is thought to be the case because this cancer exhibits few, if any, symptoms even though it has usually spread extensively throughout the abdominal cavity by the time it is detectable by clinical examination or more specialized tests. Patients with such extensive disease typically die within 3-5 years of receiving their diagnosis. If detected early enough, ovarian cancer is effectively treated by surgery, and the addition of chemotherapy may further improve the chances of successful treatment. It is for this reason that simple screening tests, able to detect ovarian cancer at early stages in its development, are expected to tremendously improve the survival of patients with this disease. Unfortunately, there are currently no screening tests available that can detect ovarian cancer 100% of the time when it is actually present, while also being able to rule out the disease in 100% of the cases in which it is actually absent. This latter property of the test is especially important because when the test is not reliable in this regard, patients without cancer may be inappropriately subjected to an invasive surgical procedure intended to confirm the 'cancer-positive' test result.Preliminary research done in the laboratory of the principal investigator has identified a chemical constituent present in the blood, which is found at higher levels in patients with ovarian cancer than in healthy people and people with other kinds of cancer. These results strongly suggested that this newly discovered marker, which is a protein likely released from the tumor, may have the ability to correctly diagnose ovarian cancer.In this grant proposal, we describe further studies, which will examine in greater detail, the ability of a test for the amount of this protein in blood to correctly diagnose the presence of ovarian cancer.